Infection of Ascaris occurs by

Options

A. tsetse fly
B. mosquito bite
C. imperfectly cooked pork
D. contaminated food and water

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks how infection of Ascaris occurs. Ascaris is a type of roundworm (nematode) that can infect humans.

2. **Analyzing the Options**: The options provided are:
- A) Fly
- B) Mosquito bite
- C) Imperfectly cooked pork
- D) Contaminated food and water

3. **Evaluating Each Option**:
- **Option A (Fly)**: Flies can carry various pathogens but are not known to transmit Ascaris.
- **Option B (Mosquito bite)**: Mosquitoes are vectors for diseases like malaria and dengue but do not transmit Ascaris.
- **Option C (Imperfectly cooked pork)**: This is associated with tapeworm infections, not Ascaris.
- **Option D (Contaminated food and water)**: This is the correct option. Ascaris eggs are excreted in the feces of infected individuals and can contaminate food and water sources.

4. **Conclusion**: The correct answer is **Option D: Contaminated food and water**. Infection occurs when a person ingests food or water that has been contaminated with Ascaris eggs.

5. **Explanation of the Mechanism**: When a person consumes contaminated food or water, the ingested eggs hatch in the intestines, leading to infection. The fecal matter of an infected person contains these eggs, which can spread the infection.